We put up a tip jar on MomsMoney.com as a way for our listeners to reward our hosts (who do the show for free) when they enjoy the show. So far, we haven't seen any action there - but we're not giving up. Who knows but that someone will listen for awhile and come back to give a host a big chunk of change?
I do occasionally tip someone's blog or forum myself so I think they can work - I just don't know how well they work overall.